Hi, I’m very new to WordPress & CSS and am slowly picking things up as I go. Can you please tell me what code I need to enter into the Quick CSS box to reduce the spacing between Content Elements?

I have 3 Promo Boxes sitting underneath each other in a vertical row. There is a lot of padding around the content in each box which I’d like to reduce. There’s also a large space between each Promo Box that I’d like to reduce.